Pump device unifying a reservoir and method for attaching the reservoir to the pump device

ABSTRACT

A pump device unifying a reservoir is disclosed. The pump device comprises a pump housing, a bracket, bolts and nuts. The pump housing comprises a front and a rear housing. The bracket is attached to the reservoir at one end thereof. The bolt has a bolt head at an intermediate portion thereof, a first thread portion formed on one side thereof and a second thread portion formed on the other side thereof, which a diameter of the first thread portion is larger than the same of the second thread portion. The nut engages to the second thread portion. The rear housing is secured to the front housing by screwing the first thread portion to the front housing through the rear housing. The nut is screwed to the second thread portion so that the other end of the bracket is fixed between the bolt head and the nut.

INCORPORATION BY REFERENCE

[0001] The present application claims priority under 35 U.S.C. §119 toJapanese Patent Application No. 2002-50873, filed on Feb. 27, 2002. Thecontents of that application are incorporated herein by reference intheir entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to a pump device on which a reservoir isattached being unified and a method for attaching the reservoir to thepump device.

[0004] 2. Discussion of the Background

[0005] A pump device that a reservoir is unified with in order tosimplify a pipe arrangement thereof is known as using for a powersteering apparatus of an automobile. A conventional pump device shown byFIG. 1 consists of a pump 2, a reservoir 3 attached with the pump 2 andattaching elements which comprise a bracket 4 and a couple of bolts 5.The bracket 4 consists of a main body 4 a which is integrated with anundersurface of the reservoir 3 and a pair of arm portions 4 b which arebent like a L-shape at the ends of the main body 4 a. As shown by FIG.2, each arm portion 4 b is inserted between a rear housing 7 of the pump2 and head 5 a of each bolts 5, and fixed with the rear housing 7 and afront housing 6 of the pump 2 by the bolts 5 in order to unify thereservoir 3 to the pump 2. In this way, the bolts 5 work used for bothof securing the rear housings 7 to the front housing 6 and fixing thebracket 4 to the pump 2. Then, since both of through holes 9 formed onthe arm portion 4 a and through holes 7 a formed on the rear housing 7are loose hole, it is difficult to tighten the bolt 5 with positioningboth of rear housing 7 and the bracket 4 exactly. Therefore, it ispossible that rear housing 7 or the bracket 4 is not secured in exactposition. Further, a performance inspection of the pump 2 is usuallyexecuted after the pump 2 is assembled, but before the bracket 4 isfixed to. Therefore, the bolts 5 have to be pulled out in order to fixthe bracket 4 after the performance inspection, and be screwed againafter being inserted into the through hole 9 of the arm portions 4 b.Then, it is possible that extraneous substances are put into the pump 2and performance of the pump 2 changes because the bolts 5 which securesthe rear housing 7 to the front housing 6 are loosened and pulled out.When the reservoir 3 has to be exchanged for new one in aftermarket, thesame problems are concerned.

SUMMARY OF THE INVENTION

[0006] In view of the foregoing, it is an object of the presentinvention to provide an improved pump device. In order to achieve theabove and other objects, a first aspect of the present inventionprovides a pump device unifying a reservoir. The pump device comprises apump housing, a bracket, a bolt and a nut. The bracket is attached tothe reservoir. The bolt has a bolt head in an intermediate portionthereof. A first thread portion is formed at one side of the bolt and asecond thread portion is formed at the other side of the bolt. The firstthread portion is screwed into the pump housing. The nut screwed to thesecond thread portion so as to secure the bracket with the bolt head.

[0007] A second aspect of the present invention provides a method forattaching a reservoir to a pump device. The method comprises preparing abolt, a bracket and a nut. The bolt has a bolt head at an intermediateportion thereof, a first thread portion formed on one side thereof and asecond thread portion formed on the other side thereof. The bracket isattached to the reservoir at one end thereof. The nut engages to thesecond thread portion. The bolt is secured to the pump device so as toscrew the first thread portion. The nut is screwed to the second threadportion so that the other end of the bracket is fixed between the bolthead and the nut.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Various other objects, features and many of the attendantadvantages of the present invention will be readily appreciated as thesame becomes better understood by reference to the following detaileddescription of the preferred embodiments when considered in connectionwith the accompanying drawings, in which:

[0009]FIG. 1 is a front view of a conventional pump device;

[0010]FIG. 2 is a cross sectional view along II-II of FIG. 1;

[0011]FIG. 3 is a front view of a pump device unifying a reservoiraccording to an embodiment of the present invention; and

[0012]FIG. 4 is a cross-sectional view along IV-IV of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] Embodiment of the present invention will be described withreference to the drawings. FIG. 3 and FIG. 4 show a pump device as theembodiment of the present invention. The pump device, for instance thatis used for a power steering apparatus, consists of a pump 10 such asvane pump, a reservoir 11 and attaching elements which are a bracket 12and a couple of bolts 13. The bracket 12 consists of a main body 12 awhich is integrated with an undersurface of the reservoir 11 and a pairof arm portions 12 b which are bent like a L-shape at the end of themain body 12 a. Each bolt 13 comprises a bolt head 13 a which is locatedat an intermediate portion thereof and is shaped into a hexagon forbeing engaged with a wrench. A first thread portion 13 b is formed onone side of the bolt 13, and a second thread portion 13 c is formed onthe other side of the bolt 13, which a diameter of the first threadportion 13 b is larger than the same of the second thread portion 13 cand a length of the first thread portion 13 b is longer than the same ofthe second thread portion 13 c. The first thread portion 13 b is screwedinto a front housing 16 of the pump 10 through a through hole 17 of arear housing 15 of the pump 10 in order to secure the rear housing 15 tothe front housing 16 so as to be turned by the wrench engaging the bolthead 13 a. A nut 18 is screwed to the second thread portion 13 c inorder to fix the arm portion 12 b of the bracket 12 between the bolthead 13 a and the nut 18 so that the second thread portion 12 c goesthrough a U-shape slot 12 c formed at each end of the arm portion 12 b.The U-shape slot 12 c is formed with the arm portion 12 b in thisembodiment, however a through hole can be adapted instead of the U-shapeslot 12 c.

[0014] An order of an assembling and a performance inspection for theaforementioned pump device will be described. First, the pump 10 isassembled so that the rear housing 15 is secured to the front housing 16after components of the pump 10 is put together into the front housing16. Then, the bolts 13 and other bolts 14 are used. The first threadportion 13 b of the bolt 13 is screwed into the front housing 16 throughthe through hole 17 of the rear housing 15 in order to secure the rearhousing 15 to the front housing 16. Next, the performance inspection ofthe pump 10 is executed. After the inspection, each arm portion 12 b ofthe bracket 12 is inserted so that the second thread portion 12 c goesthrough the U-shape slot 12 c, and the bracket 12 is fixed to the pump10 to screw the nut 18 to the second thread portion 13 c.

[0015] According to the aforementioned embodiment, performance of thepump 10 does not change and there is no fear that extraneous substancesare put into the pump 10 after the inspection or when the reservoir 11is exchanged in aftermarket, because it is not necessary that the bolts13 are pulled out. Further, assembling time of the reservoir 11 can bereduced and it becomes easily that the rear housing 15 and the bracket12 are secured in exact position, because the rear housing 15 and thebracket 12 are not secured simultaneously. Furthermore, the bolts 13 arenot turned when the nuts 18 are screwed if the bolt head 13 a and thenut 18 are tightened by same power, because the diameter of the firstthread portion 13 b is larger than the same of the second thread portion13 c.

[0016] Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereby tobe understood that within the scope of the appended claims, the presentinvention may be practiced otherwise than as specifically describedherein.

What is claimed is:
 1. A pump device unifying a reservoir comprising: apump housing; a bracket attached to the reservoir: a bolt having a bolthead at an intermediate portion thereof, and formed a first threadportion on one side thereof and a second thread portion on the otherside thereof, wherein the first thread portion is screwed into the pumphousing; and a nut screwed to the second thread portion so as to fix thebracket with the bolt head.
 2. A pump device unifying a reservoiraccording to claim 1, wherein: the bracket has a U-shape slot which thesecond thread portion goes through.
 3. A pump device unifying areservoir according to claim 1, wherein: the bracket has a through holewhich the second thread portion goes through.
 4. A pump device unifyinga reservoir according to claim 1, wherein: a diameter of the firstthread portion is larger than a diameter of the second thread portion.5. A pump device unifying a reservoir according to claim 1, wherein: alength of the first thread portion is longer than a length of the secondthread portion.
 6. A method for attaching a reservoir to a pump device,comprising: preparing a bolt which has a bolt head at an intermediateportion thereof, a first thread portion formed on one side thereof and asecond thread portion formed on the other side thereof; preparing abracket which is attached to the reservoir at one end thereof; preparinga nut which engages to the second thread portion; securing the bolt tothe pump device so as to screw the first thread portion; and screwingthe nut to the second thread portion so that the other end of thebracket is fixed between the bolt head and the nut.
 7. A method forattaching a reservoir to a pump device according to claim 6, wherein:the pump device comprises a front housing and a rear housing; and therear housing is secured to the front housing by screwing the firstthread portion to the front housing through the rear housing.
 8. Amethod for attaching a reservoir to a pump device according to claim 7,wherein: a performance inspection of the pump device is executed afterthe rear housing is secured to the front housing and before the bracketis fixed.